1. Field of the Invention
The present invention relates to pyrotechnic smoke charges containing guanidine nitrate.
2. Description of the Prior Art
The theory and techniques of natural fog formation, and in particular of artificial fog generation, are discussed briefly and broadly in TECHNIK und VERSORGUNG 1970, pp. 63 to 68. Together with the most varied agents and methods for production of artificial fog or smoke, viz. for camouflage, there are also described on pages 65 to 67 under the group of pyrotechnic fogs, chlorohydrocarbon-metal and phosphorus smoke charges. A special form of chlorohydrocarbon-metal smoke charges are those containing zinc dust as the metal, where a portion of this zinc dust may be replaced by zinc oxide and small quantities of other metal powders as reaction accelerators, e.g. aluminium powder, are present. Such smoke charges are also disclosed in GB-PS No. 127031 and Dr. H. Ellem's Modern Pyrothechnics, 1961, p. 277. Hexachlorethane is normally preferred as the chlorohydrocarbon. Along with powdered zinc and possibly zinc oxide powder such smoke charges may contain in addition to, or instead of aluminium powder, small amounts of powdery silicon, titanium, iron and/or magnesium, where possibly there may be present, moreover, even small quantities of ordinary metal-oxide powders, like powdery manganese dioxide, copper oxide or iron oxide. The phosphorus smoke charges contain along with red phosphorus, as a rule, additional constituents such as powdered metal, e.g. magnesium powder; metal oxides, like manganese dioxides or especially copper oxide, or even nitrates, like potassium nitrate or barium nitrate.
DE-PS No. 887 128 discloses a fumigant for combating vermin consisting of a volatilizing pesticide compound together with guanidine nitrate and a substance promoting the exothermic decomposition of guanidine nitrate wherein the decomposition-accelerating substance is a polynitrophenol or a polynitrosophenol. Exemplary agents of this type contain a preponderant amount of guanidine nitrate (67 or 65%), 4, 6-dinitro-o-cresol or dinitroresorcinal (18 or 15%) of pesticide, and .alpha.,.alpha.-bis (p-chlorophenyl) .beta., .beta., .beta.-trichlorethane or .gamma.-hexachlorocyclohexane (15 or 20%). By the use of chlorohydrocarbons a high output of smoke is apparently achieved. Nothing is said about the purpose of the guanidine nitrate present in this fumigant, but by its use there should obviously be effected through the gases arising from its thermal decomposition a volatilization of the other components. Metal powders and other constituents customary in pyrotechnic smoke charges are necessarily absent from this fumigant and the latter would not be suitable as a smoke charge if only because of its toxicity.
The above discussed pyrotechnic smoke charge based on chlorohydrocarbons, in particular hexachlorethane, and metal powder, in particular zinc powder, or based on red phosphorus, though distinguished by sufficiently high smoke output with good screening power, still have the drawback that they are not nontoxic to the desired degree. During screening with such smoke charges there is indeed produced hydrogen chloride or phosphorus pentoxide which can lead to severe toxic symptoms when inhaled. There have even been fatalities from this, particularly when such smoke charges were set off in more or less confined spaces and/or under conditions of too low humidity. Since a smoke, however, serves exclusively for purposes of camouflaging it must be basically nontoxic. This requirement is not fulfilled by smoke charges based on chlorohydrocarbons and powdered metal on account of the hydrogen chloride generated by them, and the same is true to a somewhat smaller degree in the case of smoke charges based on red phosphorus, in the volatilization of which phosphorus pentoxide is formed.